Vacuum-tube contact



Aug. l1, 1925.

J. J. GHEGAN VACUUM TUBE CONTACT Filed Feb. 12, 1924 wveutoz Jom J @hegt/rz t @ttm Patented Aug. "1l, 1925.

1,549,355. .PATENT OFFICE.

JOHN J. GHEGAN, OFAST ORANGE, NEW JERSEY.

'VACUUM-TUBE CONTALT.

Application iiled February 12, 1924. Serial No. 692,271.

To all 'whom t may concern:

. Be it known lthat I, J oHN J. GHEGAN, a citizen of the United States, and a resident of East Orange, county of Essex, and State of VNew Jersey, have invented certain new and useful Improvements in Vacuum-Tube Contacts, of which the following is a speciflcation.

- The present invention -relates particularly, but not` exclusively to vacuum tubes of the type suchy as are used in radio receiving sets. ,These tubes have contacts in the form of projecting prongs designed t-o eng'age correspondingly located spring contact strips in the sockets which are provided to receive such tubes. The areay of engagement between the ends of the prongs and the socket contacts is quite limited because of the small, size of the prongs and the angle to which the socket contacts are deflected by the prongs when the tube is forced down to its seat in the socket. This limited area of contact frequentlyV gives rise to trouble in the set-because of the oxidation which takes place at this point, particularly with rises in current value; which occur during operation of the set. Thisconnection also is an inherent weakness in the set because of the readiness with which it is affected by the presence Aof dust and moisture.

The objects of this invention are to overcome this weakness and to provide in simple, practical forni, a means for establishing and maintaining-a full-area perfect connection between the 'contacts of the tube and socket.

The foregoingand other objects are at'- tained in the present invention by a novel construction and relation of parts, the de-l tails of which will fully appear in the course of the following .specilication` In the drawing accompanying' andwform- 'ing part of thisspecification, vthe invention is illustrated in one of its simplest embodiments, Figure 1, being apart sectional -side elevation showing a vacuum tube equipped with the invention, engaged in 'its Vsocket and Figure' 2 being anenlargedfragmentary to automatically adjust itself and seat iirmly on the `contact strip regardless of the relaviewshowing in detail theengagement" of the cooperative tube and socket contacts. Thetube illustrated is of a standard type having projecting 'filament contact studs 5,

6 and similar plate and grid .contacts .7,l 8, together with a projecting pin' 9 on the side of the tube base for insuringproper registry .with the l socket contacts.

fnl-9 socket illustrated :likewise is of a all the springs, the part-sA are usually so designed that' the tube will be pushed down in the socket far enough to actually deflect and 'bend the springs downwardly in the manner illustrated. `This angularity of the springs, it will be observed, further reduces the possible area of contact between the springs and pins.

In the embodiment ofthe invention here' illustrated a fully effective and lasting contact iS made by surrounding the contact pin. with a helical spring 15 of bronze or other good conducting material,'and which is suficiently resilient and enough larger. than the pin to adjust itself to the angularity of the contact spring to seat itself fiat againste the face of the spring after the manner indicated in Figure 2. One or a number of these springs may be used on each tube, as found desirable. Usually, however, at least the two filament contacts will be so equipped to insure a full current supply to the filament.

The helical sprin are preferably secured at their. upper en s in someA fixed or permanent manner, as by soldering them to the contact pins, as indicated at 16. This provides erfect conductivity betweenthe contact .pms and the surrounding sprmgs and also prevents `the springs from dropping olf .such position that the lowermost convolution will be projected beyond the end of the pin. These features with the looseness of the spring about the pin enable the spring tive angularity between the two. The lower end of the springis usually faced oft` flat so that substantially a full convolution will The helical contact springs are relatively inexpensive, can be easily applied to exist- 'lie in engagement with the socket contact.

ing -forms of tubes and provide a perfect and lasting contact relation between the tube and vsocket elements. This prevents the development of high resistance points in the tube and socket connections and makes this part of the set just as highly conductive as the soldered and other permanent joints pro vided in the balance of the set. With the more inventlon, it has been found that a receiving set becomes more selective and more eilicient in every way.

What is claimed is:

1. A vacuum tube having Contact pins and helically coiled springs engaged on said pins, means for xedly securing said coiled springs on said pins at the ends nearest the base of the tube, said vcoiled springs having contact making end portions loosely surroundin the pins and projecting beyond the ends o the pins when unrestrained to thereby form self-adjusting contacts movable longitudinally and laterally with respect to the pins to.,l automatically adjust themselves in flat face engagement with angularly related spring contact strips of a tube socket. j

2. A vacuum tube having a projecting pin contact and a helically coiled spring engaged on suchfpin, means for ixedly securing said coiled spring to the pin at the perfect conductivity aiorded by thisend nearest the base of the tube, the balance of said spring being freel adjustable about the pin with the end of t 'e spring'proecting when unrestrained beyond the en of the pin.

3. A 'vacuum tube having a, projecting pin contact and a: helical auxiliary. sprin contact .loosely surrounding said pin an having a portion adjacent the base of the tube secured to the pin by a permanent soldered -oint.

4. A t ermionic tube having projecting pin contacts for'the filament and auxiliary coiled spring contacts concentrically engaged on and carried by said filament in contacts, and means for iixedly securlng said coiled spring contacts on the pin contacts.

5. A thermionic tube comprising a base, terminal prongs carried by said base, auxiliary resilient contact means carried by said prongs, means for ixedly securing the same on the prongs, said contact means tending to project beyond said prongs whereby to engage socket contacts engaged by the prongs and thereby lower the contact resistance.`

In witness whereof I have hereunto set my hand this 8th day of February, 1924.

JOHN J. GHEGAN. 

